1. Field of the Invention
This invention relates generally to the generation of time delayed audio signals, and more particularly to the generation of such signals for use in simulating auditorium ambience, including reverberations.
2. Prior Art
It is universally recognized that, irrespective of the quality of reproduction, music played through a conventional stereophonic or multi-channel high fidelity reproducing system in a small room, such as a residential living room, will not sound the same as does live music in an auditorium. This difference is due in no small part to the difference in the reverberation characteristics of the two environments. In a living room, the walls are close together so that reflections are close together temporally, and are rapidly damped out due to absorption by the walls and furnishings. In an auditorium or hall, on the other hand, the transit times of the reflections are substantially longer, and each sound generally persists for a longer time.
It has been known in the prior art to simulate auditorium reverberations in a small room by placing extra loudspeakers behind the listeners and feeding a reduced volume delayed signal thereto. It has also been known to recirculate the reduced volume signal through the delay means repeatedly to simulate multiple reflections. These prior art attempts to reproduce the ambience of an auditorium in a small listening environment have generally suffered from a number of shortcomings which have been overcome by the present invention. Among the shortcomings of the prior art approaches to auditorium ambience simulation which have been overcome by the present inventions are inappropriate acoustic modeling, insufficient control flexibility, poor signal quality, inadequate dynamic range, and poor signal to noise ratio.